Question

Assertion (A): Restriction endonuclease recognises palindromic sequence in the DNA and cuts them.
Reason (R): Palindromic sequence has two unique recognition sites PstI and PvuI recognised by the restriction endonuclease.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
• C. (A) is true, but (R) is false.
• D. (A) is false, but (R) is true.

Hint:

Restriction endonucleases like PstI and PvuI each recognize specific palindromic sequences, but a single palindromic sequence is typically recognized by one enzyme, not two.

Answer 1

The Correct Option is C

Step 1: Restriction endonucleases recognize specific palindromic sequences in DNA and cut them, making Assertion (A) true.
Step 2: A palindromic sequence is a DNA sequence that reads the same forward and backward on complementary strands, but it does not inherently have "two unique recognition sites" like PstI and PvuI, which are specific restriction enzymes with their own recognition sequences, making Reason (R) false.
Step 3: Since (R) is incorrect, it cannot explain (A).
Thus, (A) is true, but (R) is false.